3 Answers
3

Your third option will be the option to consider here. A proper 301 redirect to the new content will let the crawlers know, that the content has moved. They will keep the page rank and move it to the new domain.

As far as your Webmaster Tools are concerned, you will have to use the Change of Address tool, to let Google know, you moved your content. It is exactly, what you're looking for.

I concur with what the previous commenters have said.
I would also recommend using an on-page checker (a http://www.w3.org/ checker or an seo site auditor http://www.link-assistant.com/website-auditor/) to check if the redirects are set up correctly.
this will also show you what pages have canonical tags, special robots.txt instructions and other SEO-specific things you might overlook in the process of moving the site.